Existence abounds with relativity, thus processes, procedures, systems, and results all have relative error caused by deviations or inconsistencies that result in failures. This accounts for the statistical standard errors, confidence intervals used in statistical analysis and inference. This applies directly in engineering reliability studies, by considering uncertainties which could result in deviations in quality of engineering output. Provisions are made for worst or critical cases from analysis of scenarios of failures in engineering products due to various factors.
Factors affecting reliability of products include:
- Deficiency in design: This could be small safety margins possible due to poor design information or data about materials, standards, and other resources.
- Poor quality management – Inconsistency to quality benchmarks, which results deviations in batches of products quality needs to be controlled with the help of quality assurance and control methods.
- Environmental conditions – changes in environmental parameters – temperature, humidity, chemical reactions like oxidation, and wind pressure may result in changes in engineering products.
- Production defects and errors.
- Overburden stress – Accidental loads, over-heating of materials, overloading of engineering products invariably leads to fatigues and failures in forms of buckling, bending, cracking, twisting, shear, and other forms of failures.
- Wear and tear – weathering, loss of properties due to age, and friction resulting from interaction between parts, and members of engineering products could result in wear due to abrasion between surfaces, and tear in extreme cases.
A CASE OF FIRE PROTECTION LOADING ON STRUCTURAL ELEMENTS: Buildings are structurally designed with provision of imposed dead loads due to fire protection services, like – fire protection piping and pipe supports, sprinklers, discharge sprays and nozzles, aerosol cannisters, foam generators, foam pourers, foam chambers, fire pump set and other appurtenances. Live loads due to fluid action of fire extinguishing fluids and mechanical vibrations of fire pumps are also considered. Loading of engineering service systems is not fully determined at the time that the structural design is carried out, hence provision for loads is generated and distributed on structural members as point loads, uniform or varying linear loads, or uniform or varying area loads. There is high tendency of significant changes of imposed loads due to fire protection service, and live loads due to fire suppressants conveyed in the piping systems, as well as discharge equipment which usually exhibit dynamic forces like fluid pressure, and flow velocity. Earthquake vibrations, which generates dynamic loads and aftershocks are provided with safety factors. Safety margins or safety factors specifically address as PARTIAL FACTOR OF SAFETY is added to estimated load, and analyzed load to account for any major negative or positive deviations that may occur so as to take care of possible failures due to overloading. “Eurocodes 2 (EN 1992) – Design of Concrete Structures” specifies serviceability limit state design of structures for fire resistance, deflection, durability, overall stability, cracking and excesses vibration are covered. The ultimate design loads are accessed by using load combination of dead loads, live loads, accidental loads, and earthquake loads obtained by multiplying the partial factors of safety for each load type. Dead and live loads of fire protection services are thus enhanced by engineering reliability design so as to prevent failures in the case of structural reliability.
Safety margins are very important in engineering reliability to take care of inconsistencies or deviations that occur due to slight design assumptions, construction errors, and other criteria that could alter quality of engineering products.
Safety engineering methods, such as Process Hazard Analysis and Quality Management like Engineering Safety Review, HAZOP (Hazard and Operability Study), Safety Integrity Level (SIL), Layer of Protection Analysis (LOPA), Quality Assurance and Quality Control (QAQC), Risk Assessments (RA), and Reliability, Availability, and Maintainability Studies (RAMS) are good ways that can be employed in assessment, monitoring, and control of engineering reliability.
Visit here for more information about us. Our past project experience is also value proposition & project experience. Our telephone contacts are + 234 809 476 7724 / 803 726 7341 /704248 3618. We can also be reached via mail at info@scspng.com.
William Nwaogu, Technical Advisor
Safety Consultants & Solution Providers Limited
